1. Field of the Invention
The present invention relates to a valve device facilitating start-up of an internal combustion engine by relieving compression pressure in a combustion chamber when the engine is started up.
2. Description of the Background Art
When such an engine is started up with a starter, counterforce against the compression pressure generated by a piston of the engine acts on the starter. Therefore, when a recoil starter is employed, a large amount of force is needed for driving it. Alternatively, when a self-starting motor is employed, it should be a big motor with high power.